JP6801085B2 - Methods and equipment for aligning boards - Google Patents

Description

The present invention relates to a method of aligning and contacting a first substrate and a second substrate according to claim 1 and a corresponding apparatus according to claim 10.

In the semiconductor industry, aligners are used to align multiple substrates, especially wafers, to each other so that these substrates are joined together in subsequent process steps. This bonding process is called bonding.

The alignment process of providing alignment marks on the surface of the substrate to be bonded is called face-to-face alignment.

The substrate is opaque to the electromagnetic beam used for measurement so that the position and orientation of the alignment marks can be detected and / or identified from the outer substrate surface, opposite the substrate surface to be bonded. In some cases, alignment marks are detected between the substrates using image detecting means before the substrates are brought close to each other.

This has various drawbacks, such as particle contamination by the camera and a large distance between the two substrates because the camera is arranged between the two substrates for detection. For this reason, misalignment occurs when they are brought close to each other.

Improvements in face-to-face alignment are shown in the alignment device of publication US Pat. No. 6,214,692 (US6214692B1), which can be regarded as the closest prior art. In this alignment device, in order to form a system having two reference points, two groups of optical elements each having two optical elements facing each other are used, and the substrates alternate with respect to this system. Positioned to. These reference points are the intersections of the optical axes of the two optical elements facing each other.

The problem with this prior art is that with the disclosed open-loop control schemes, the ever-increasing demands for alignment accuracy can no longer be reached.

Publication US Pat. No. 6,214,692 (US6214692B1) is based on the comparison and positioning correction of two images of alignment marks. The directions of the alignment marks on the two face-to-face substrates are individually detected using the camera system. The positioning table (board holder and stage) is driven and controlled from the calculated relative direction and relative position of the alignment mark, whereby the incorrect position is corrected. The positioning table has a guide sensor and an increment type displacement sensor arranged near the drive unit.

Therefore, an object of the present invention is to show a device and a method for aligning and contacting substrates, which can align and contact substrates more accurately and more efficiently.

This problem is solved by the characteristic configurations of claims 1 and 10. An advantageous development of the present invention is set forth in the dependent claims. Within the framework of the present invention are all combinations consisting of at least two of the plurality of characteristic configurations shown in the specification, claims and / or drawings. If a range of values is specified, the values within the mentioned boundaries are also disclosed as boundary values and can be claimed in any combination.

The underlying idea of the present invention is an additional (especially third) alignment that is adhered to either one of the plurality of substrates to be aligned or the substrate holder prior to alignment. It is to additionally detect the mark. In particular, this additional alignment mark is not placed on the contact surface of the substrate. Preferably, this additional alignment mark is placed on the surface of the substrate or the surface of the substrate holder that is located opposite the contact surface or parallel to the contact surface.

Mutual alignment of the substrates is performed indirectly, in particular, using a plurality of alignment marks provided on the contact surfaces of the substrates. The alignment marks on the opposing surfaces of the opposing substrates are particularly complementary to each other. The alignment mark may be any mutually alignable object, such as a cross, circle or square or propeller-like formation or grid structure, especially a phase grid for the spatial frequency domain.

Alignment marks are preferably detected using an electromagnetic beam of a predetermined wavelength and / or wavelength range. Included in these are currently infrared beams, visible or ultraviolet beams. However, it is also possible to use shorter wavelength beams, such as EUV or X-ray beams.

One aspect of the present invention (particularly unique) is that alignment is performed, in particular, using only the detection of additional alignment marks. "Detection only" means that another alignment mark (particularly the first and second alignment marks) is not detected or cannot be detected during alignment.

According to one advantageous embodiment of the present invention, the first substrate and the second substrate are provided with a space A between the first contact surface and the second contact surface in the Z direction. It is arranged between the substrate holder of No. 1 and the second substrate holder. The spacing A is particularly less than or equal to 500 micrometers, particularly preferably less than or equal to 100 micrometers, optimally less than or equal to 50 micrometers, and ideally less than or equal to 10 micrometers.

The method according to the invention is, in particular, by any electromagnetic beam, in particular by UV light, more preferably by infrared light, most preferably by visible light and / or a first alignment mark and a second alignment mark. It is a method of aligning at least two substrates face-to-face by sequentially opening optical paths for observing, and here, at least 1 in order to accurately reproduce the substrate position and the substrate holder position. It is stipulated to supplement two additional optical paths, which are not located or extend between the substrates when aligning the substrates, and can be detected externally. become.

The method according to the invention is, in particular, additional XY position information and / or additional XY position information detected by an additionally mounted detection unit and / or measurement system and closed loop control system and used for open loop control of alignment. Positioning accuracy is improved by using direction information.

To this end, the apparatus according to the invention has a particularly software-supported control unit that is used to control the steps and components described herein. In the present invention, it is understood that the closed control loop and the closed loop control are included in this control unit.

The X-direction and the Y-direction and the X-position and the Y-position are understood as a direction or a position extending in an XY coordinate system or an arbitrary Z plane of the XY coordinate system. The Z direction is arranged orthogonal to the XY directions.

The X and Y directions correspond particularly to the lateral direction.

Positional features are derived / calculated from the position and / or direction values of the alignment marks on the substrate and from the alignment marks on the substrate holder.

In the present invention, in particular, at least one additional positional feature is detected by at least one additional measurement system having a new additional optical path. At least one additional alignment mark is preferably provided in the vicinity of the alignment mark on the substrate.

Thus, the method according to the invention and the apparatus according to the invention particularly have at least one additional measurement system and / or closed loop control system, where additional measurements are used and another plurality of detection units. The alignment accuracy is improved by the correlation with one of the plurality of measured values of. Directly observe the alignment marks by correlating at least one of the plurality of alignment marks measured in the bonding interface between the contact surfaces with the alignment marks that are also visible when aligning the substrate. This allows real-time measurement and closed-loop control during alignment. As a result, the alignment accuracy of the substrate is improved.

Additional alignment marks are specifically placed on the back of the board holder.

An additional unique correlation is formed between the positional feature on the substrate holder and the positional feature on the substrate, which is particularly preferably not changed until and during alignment. ..

The additional positional features added to the substrate holder, which are uniquely correlated with the positional features on the substrate, allow the direct observation of the positional features on the substrate to be replaced by the direct observation of the positional features on the substrate holder. The advantage of this is that virtually always the observable portion of the substrate holder can be placed within the field of view or measurement area of the additional measurement system.

By actively feeding back data for positioning and position correction, accuracy is improved compared to open-loop controlled positioning in the prior art. This is because the closed control loop can control the actual state of the position. This measures the section already traveled, in particular, rather than traveling a preset section with a predetermined number of increments, thereby between the target and actual values, especially for speed and / or acceleration. You can make a comparison. An object of the present invention is to improve the accuracy of alignment of two substrates, particularly by using a method capable of observing alignment in real time from outside the bonding interface. Here, the substrates are arranged particularly at the minimum distance from each other, and there is preferably no device object between the substrates.

The core idea of the present invention is, in particular, to introduce at least one additional measurement system and closed-loop control system, and to include existing measurements and newly detected additional position and / or direction values. Is to connect. Alignment marks measured at the bonding interface and alignment marks that are particularly directly detectable during alignment and are on the board holder, especially on its back and / or on the board, especially on its back. By correlating, additional alignment marks can be directly observed, enabling real-time measurement and real-time closed-loop control. By such means, the alignment accuracy is improved.

During the detection of the first alignment mark, the second substrate and the second substrate holder are moved out from the optical axis of the first detection unit in the XY directions, whereby the detection becomes possible. ..

During the detection of the second alignment mark, the first substrate and the first substrate holder are moved out from the optical axis of the second detection unit in the XY directions, whereby the detection becomes possible. ..

Device The device of the present invention that aligns at least two substrates comprises, in particular, two optical elements or detection units that are aligned with each other and has at least one optical system whose optical paths preferably intersect at a common focal point.

The optics include, according to an advantageous embodiment, a beam forming element and / or a deflecting element such as a mirror, a lens, a prism, particularly a light source which is Koehler illumination, and a camera (CMOS sensor or CCD, or phototransistor). Image detection means such as surface or row or point detection means), moving means for focusing, and evaluation means for closed-loop control of the optical system are included.

In one embodiment of the present invention of this device, an optical system and a rotation system for substrate positioning based on the principle of turnover position adjustment are used. See Friedrich Hansen's Justierung, VEB Verlag Technik, 1964, Section 6.2.4, Umschlagmethode for this. Here, at least one measurement at a predetermined position and at least one measurement at a turnover position rotated 180 ° and oriented in the opposite direction are performed. There is no particular eccentric error in the measurement results obtained in this way.

One evolution of the apparatus according to the invention includes two optics, particularly identical and of the same structure, with optical elements that are aligned with each other and fixed relative to each other.

One evolution of the device according to the invention includes more than two identical optics with aligned optics.

Further, the apparatus according to the present invention includes a substrate holder for accommodating the substrate to be aligned.

In another embodiment of the apparatus according to the invention, at least one substrate holder that is at least partially transparent, preferably 95% or more transparent, to observe the two substrate surfaces particularly simultaneously at a given location. To use.

In another embodiment of the apparatus according to the invention, at least one substrate holder having multiple openings and / or through holes and / or inspection windows for observing two substrate surfaces particularly simultaneously at a given location. To use.

Further, the apparatus according to the invention may include a system for forming prebonds.

Further, the apparatus according to the present invention preferably includes a plurality of drive systems, guide systems, fixation systems and measurement systems for moving, positioning and aligning the optical system and the substrate holder and / or substrate with each other. Includes mobile devices.

These mobile devices can form arbitrary movements as a result of individual movements, whereby these mobile devices operate precisely with high speed coarse positioning devices that do not preferably meet accuracy requirements. Precise positioning device and can be included.

The target value of the position to be reached is an ideal value. The mobile device approaches this ideal value. Reaching a predetermined range around the ideal value can be understood as reaching the target value.

A rough positioning device means that the reaching accuracy and / or the repeatability is 0.1% from the target value based on the rotation range in which 360 ° is one rotation in the entire running path or the rotatable rotary drive unit. As described above, it is understood that the positioning device preferably deviates by 0.05% or more, particularly preferably 0.01% or more.

Thus, for example, in a coarse positioning device having a travel path of 600 mm or more, a reach accuracy of 600 mm × 0.01%, ie 60 micrometers or more, results in residual uncertainty (Restunsicherheit).

In another embodiment of coarse positioning, the residual uncertainty of reach or repeatability is 100 micrometers or less, preferably 50 micrometers or less, and particularly preferably 10 micrometers or less. In this case, the amount of thermal disturbance should be considered together, preferably together.

The coarse positioning device plays the role of positioning with sufficient accuracy only when there is a deviation in the processing range of the corresponding precision positioning device between the actual position actually reached and the target value of this position. Fulfill.

An alternative coarse positioning device is sufficient only if there is a deviation of half the processing range of the corresponding precision positioning device between the actual position actually reached and the target value at this position. It plays a role of positioning with accuracy.

A precision positioning device is ideally one in which the residual uncertainty of reach accuracy and / or repeatability is 500 ppb or less, preferably 100 ppb or less, based on the overall travel path or rotation range from the target value. In such a case, it is understood as a positioning device when it does not exceed 1 ppb.

Preferably, the precision positioning device according to the invention is ideally 5 micrometers or less, preferably 1 micrometer or less, particularly preferably 100 nm or less, particularly very preferably 10 nm or less, and in the optimum case 5 nm or less. In a typical case, it has an absolute positioning error of 1 nm or less.

The device of the present invention and the corresponding method have at least two positioning devices with maximum accuracy and reproducibility. It is possible to use the concept of mutual error correction for the quality of substrate alignment. Therefore, when misalignment (twist and / or misalignment) of the substrate and the corresponding positioning device is known, the position of another positioning device and another substrate is adjusted and corrected using the correction value or the correction vector. As a result, the positioning accuracy can be improved. At this time, by open-loop control or closed-loop control, how coarse positioning and precise positioning are used for error correction, or only coarse positioning or only precise positioning is used is twisted and / Or it is a matter of magnitude and type of deviation.

In the text that follows, the positioning device (coarse positioning device or precision positioning device or combined positioning device) and the positioning means are used as synonyms.

Alignment of a plurality of substrates with each other can be performed at all six degrees of freedom of motion according to the present invention. That is, it can be performed in three translational motions according to the coordinate directions x, y, and z, and three rotational motions around the coordinate axis direction. In the present invention, the movement can be performed in any direction and direction. Substrate alignment preferably includes, among other things, passive or active wedge error compensation according to the disclosure of European Patent No. 2612109 (EP2612109B1).

The robot for transporting the substrate is included in the moving device. The fixing portion may be incorporated as a component or functionally incorporated into the mobile device.

Further, the apparatus according to the invention preferably performs the described steps, particularly the flow of movement, makes corrections, analyzes and stores the operating state of the apparatus according to the invention, and is preferably a closed loop control system and /. Or it includes an evaluation system, especially a calculator.

The process is preferably created as a procedure manual and executed in a machine-readable form. A procedure manual is a collection of optimal values for functionally or process technically relevant parameters. By using the procedure manual, the reproducibility of the manufacturing flow can be guaranteed.

Further, the apparatus according to the invention, according to one advantageous embodiment, is a power supply system and an auxiliary system and / or a supplementary system (compressed air, vacuum, electrical energy, hydraulic pressure, refrigerant, liquid such as heat medium, temperature. Includes means and / or equipment for stabilization, electromagnetic shield).

In addition, the devices according to the invention include frames, exteriors, active or passive subsystems that suppress or dampen or extinguish vibrations.

Measurements Further, the apparatus according to the invention includes at least one measurement system, preferably equipped with a measurement unit for each axis of motion, which can be carried out specifically as a displacement measurement system and / or an angle measurement system.

It is also possible to use a tactile or tactile measuring method or a non-tactile measuring method. The measurement standard scale, the unit of measurement, may be a physical or material object, in particular a reference device, or may be implicitly included in the measurement method, such as the wavelength of the beam used.

At least one measurement system can be selected and used to reach alignment accuracy. The measurement system implements the measurement method. Here, in particular
Induction and / or capacitive and / or resistance and / or comparison, especially optical image recognition, and / or ... (especially a glass reference scale or interferometer as a reference). Incremental or absolute values (using a laser interferometer or electromagnetic reference scale) and / or propagation time measurement (Doppler, time of flight) or another time detection method, and / or trigonometry, Especially laser trigonometry,
-Autofocus and / or-Intensity measurement methods such as fiber optic distance measuring instruments can be used.

Additional Measuring Systems with Variants, Substrate Holders In addition, one particularly preferred embodiment of the apparatus according to the invention is XY of one of a plurality of substrates and / or a plurality of substrate holders. It includes at least one additional measurement system that detects the position and / or alignment direction and / or angular position with respect to a given reference, especially with respect to the frame. The frame may be provided, in particular, with a portion consisting of hard natural ore or mineral cast or spheroidal graphite cast or hydraulic concrete, the frame being particularly vibration dampening and / or vibration insulating. And / or configured to eliminate vibration.

In the present invention, measurements can be specifically combined with each other and / or referenced and / or correlated with each other, thereby measuring one alignment mark and thereby another position associated therewith. The position of the alignment mark can be estimated.

In one embodiment according to the invention, there is one substrate holder position relative to the reference, especially with respect to the first alignment mark on the first substrate and / or the second alignment mark on the second substrate. Detected at a point (or location or measurement spot or field of view).

In another embodiment according to the invention, the position of the substrate holder is detected at exactly two points relative to the reference.

In another embodiment according to the invention, the position of the substrate holder is detected at exactly three points relative to the reference, which specifies the position and orientation of the substrate holder.

In the first embodiment of the present invention, in order to locate at one point or two points or three points or an arbitrary number of points, an optical pattern recognition using a camera system and a substrate holder are attached. Patterns can be used. The pattern is detected in the real-time system, especially continuously during alignment.

The cited measurement method can also be used for positioning.

In the present invention, in particular, the reverse can be considered by attaching the detection unit to the substrate holder and attaching the alignment mark to the frame.

In an advantageous embodiment, the closed-loop control unit (and / or the open-loop control unit) is particularly continuous, particularly continuous, so that detection, evaluation, and open-loop control can be performed at any time point, especially continuously. The pattern is distributed over an area wider than the field of view of the image detection unit of the detection unit for the purpose of supplying the measured values.

In another embodiment of the device according to the invention, at least one of the plurality of substrate holders has a through opening for detecting alignment marks from the mounting surface of the substrate.

It is advantageous in the present invention that at least one of the plurality of substrates has at least one alignment mark on the surface to be bonded (contact surface) and at least on the opposite surface (mounting surface). This is the case when it has one alignment mark.

These alignment marks are preferably a plurality of evenly distributed alignment marks that can be particularly uniquely associated with each other on at least one mounting surface of the plurality of substrates. The alignment mark on the mounting surface can be correlated with the XY position and / or alignment direction of the alignment mark on the same substrate, at least with respect to its XY position and / or alignment direction. As a result, the position can be continuously specified until the boards come into contact with each other while the boards are loaded and aligned.

In one evolution of the invention, the alignment marks on the mounting surface are particularly evenly distributed, except for the edge zone (edge exclusion zone) of the substrate.

In at least one other embodiment of the plurality of substrates, the plurality of alignment marks on the mounting surface are uniquely distributed to the contact surfaces of the same substrate and the alignment marks arranged on the contact surfaces. Will be done.

In contrast to the identification of the XY position at at least one point, in another embodiment of the invention, correspondingly, in order to identify the XY position of the substrate holder and / or to specify the orientation, In particular, at least one interferometer with a monolithically configured reflector can be used. The number of interferometers is particularly the same as the number of reflective surfaces of the reflector.

In particular, the substrate holder formed from the monolithic block preferably has at least two of the following plurality of functions. That is,
-Fixing the substrate using vacuum (vacuum track, joint)
-Preferably mechanical and / or hydraulic and / or piezoelectric and / or pyroelectric and, in particular, disclosed in European Patent No. 2656378 (EP2656378B1), WO 2014/191033 (WO2014191033A1). / Or shape compensation for deforming the substrate using a pyroelectric operating element (measurement reference device, reflective surface and / or prism, especially reflector for interferometer, dragonfly and / or dragonfly field, formed in two dimensions Measurement reference device, 3D reference device, especially stage) Position identification and / or direction identification / movement (guide track)
Have.

The mobile device according to the invention, which is not used for fine tuning, is preferably configured as a robotic system with an incrementing displacement sensor. The accuracy of this moving device for auxiliary movement is separate from the accuracy of alignment of the substrate laminate, which allows this auxiliary movement to be less than 1 mm, preferably less than 500 micrometers, in particular. It is preferably performed with a low repeatability of 150 micrometers or less.

The open-loop control and / or closed-loop control of the mobile device according to the invention for (horizontal) alignment (fine tuning) is particularly in the XY position and / or alignment direction detected by another measuring means. It is done based on. The accuracy of this mobile device is preferably 200 nm or less, preferably 100 nm or less, particularly preferably 50 nm or less, particularly extremely preferably 20 nm or less, optimally 10 nm or less, and ideally 1 nm or less.

Method A first embodiment of the alignment method according to the invention includes the following, in particular at least partially sequential and / or simultaneous steps, in particular the following order:

First processing step: The first / lower substrate is loaded into the first / lower substrate holder with the mounting surface facing down. A first alignment mark is provided (exists) on the opposing surfaces (contact surfaces).

Second processing step: Using a moving device, especially for coarse adjustment, place the first / lower substrate in the field of view of the detection position of the first / upper detection unit of the optical system, substrate holder. Move with.

Third processing step: If the optical system has not already been processed by the second processing step, the optical system is moved to the detection position. The option allows you to self-calibrate the optics already at this stage or before you start moving to the detection position.

Fourth processing step: The first / upper detection unit is focused on the pattern to be identified of the first alignment mark, which is arranged on the contact surface to be bonded of the substrate.

Optionally, the optical system allows the second / lower detection unit to be positioned in the focal plane of the first / upper detection unit.

Fifth processing step: Detecting the first alignment mark, especially using pattern recognition. At the same time, the additional measurement system (with a third detection unit) according to the invention, preferably by synchronizing with the first detection unit, preferably in a surface separate from the contact surface, the first substrate. Detects the XY position and / or alignment direction of the holder and / or the first substrate.

Sixth processing step: Clamping the position of the optics, especially mechanically and / or electronically and / or magnetically, especially by zeroing all degrees of freedom.

Seventh processing step: The optical system adjusts the position of the second / lower detection unit on the focal plane of the first / upper detection unit.

Optionally, this alignment is performed and omitted following the fourth processing step.

Eighth processing step: Abstraction and / or calculation is performed by a closed-loop control computer and an evaluation computer (particularly in an open-loop control unit) in order to obtain a measurement result for open-loop control of alignment. That is, the closed-loop control computer and the evaluation computer form a correlation of the measurement results of the optical system and the (third) additional measurement system in particular, and in particular, the first / lower substrate holder and the first /. This result is stored as a target value in the XY position and / or the alignment direction of the lower substrate.

Ninth processing step: The first / lower substrate holder is moved from the field of view (beam path for detection) of the optical system. As a result, the optical path to the first detection unit is not blocked. The optics preferably remain fixed in succession.

Tenth processing step: The second / upper substrate is loaded into the second / upper substrate holder. This processing step can be performed in advance of one of a plurality of preceding processing steps.

Eleventh processing step: Move the second / upper substrate holder together with the second / upper substrate into the field of view of the optical system.

12th processing step: The second / lower detection unit of the optical system searches for and detects the alignment mark on the second / upper substrate in the same manner as the first / lower detection unit. At this time, the optical system does not move mechanically, but it is possible to correct the focusing. However, preferably, the focusing movement is not performed either.

Thirteenth processing step: The second / upper substrate and the second / upper substrate holder block the optical path of the first / upper detection unit, thereby blocking the optical path of the first / upper in the aligned position. The contact surface to be bonded on the lower substrate cannot be directly observed / detected.

14th processing step: The alignment error is obtained by the closed loop control computer and the evaluation computer. Please refer to the disclosures of US Pat. No. 6,214,692 (US6214692B1) and International Publication No. 2014/202106 (WO2014202106A1). Especially, the alignment error vector is created from the alignment error. Following this, in particular at least one correction vector is calculated. The correction vector may be a vector parallel to and in the opposite direction to the alignment error vector, whereby the sum of the alignment error vector and the correction vector becomes zero. In special cases, another parameter can be considered in the calculation of the correction vector, which makes the result different from zero.

Fifteenth processing step: The XY position and / or alignment direction of the second / upper substrate (including the substrate holder) is set according to the correction vector and subsequently clamped, thereby the calculated position. Misalignment is at least minimized and preferably eliminated.

16th processing step: After clamping / fixing the second / upper substrate, the second / lower detection unit detects / checks the XY position of the upper second substrate again. .. This allows the displacement and / or twist caused by the clamp to be identified and minimized, especially removed by repeating the twelfth to fifteenth processing steps.

Alternatively, the detected deviations and / or twists can be considered to create correction values and / or correction vectors, which can be considered to remove them in subsequent processing steps. .. The correction value for the deviation is preferably 5 micrometers or less, preferably 1 micrometer or less, particularly preferably 100 nanometers or less, particularly extremely preferably 10 nanometers or less, and in the optimum case 5 nanometers or less, ideal. In the case it is less than 1 nanometer. The correction value for twist is ideally 50 microradians or less, preferably 10 microradians or less, particularly preferably 5 microradians or less, particularly extremely preferably 1 microradian or less, and optimally 0.1 microradians or less. In the case it is less than 0.05 microradians.

In the first 5 processing steps, as in the 1st 2 processing steps, at least one measurement of the position before fixing the upper substrate and at least one measurement of the position after fixing the upper substrate are performed. Can be done. According to the present invention, it is possible to consider the correction of repeated errors, and the next processing step is executed only when a predetermined accuracy requirement (threshold value) is reached.

1st 6th processing step: Return the 1st / lower substrate holder to the already detected position and direction of the target value (see 8th processing step). In this case, the XY position and alignment direction of the lower substrate holder (along with the substrate) are controlled in real time, especially by the additional measurement system. The first alignment mark on the first substrate cannot be observed because the optical path is blocked by the clamped upper substrate holder.

1st 7 processing steps: The actual XY position and alignment direction of the 1st / lower substrate holder is modified until the difference from the target value becomes zero, but at least above a predetermined threshold. It will be fixed until it disappears.

Optional 1st 8 processing steps: Join the substrates. Please refer to the disclosure contents of Publication International Publication No. 2014/191033 (WO2014191033A1).

1st 9 processing step: The substrate laminate is unloaded from the apparatus.

Included in the alternative second embodiment of the alignment method according to the invention is the following modification of the loading order for the upper and lower substrates to the first embodiment.

As a first processing step according to the present invention, the first / lower substrate is loaded into the first / lower substrate holder.

As a second processing step according to the present invention, the second / upper substrate is loaded into the second / upper substrate holder.

Subsequently, the processing steps of the first embodiment are applied in the same manner.

In a third embodiment of the method according to the invention, the first method and / or the second method is modified so that the up and down directions are exchanged both in the apparatus and the method according to the invention. To do. Therefore, especially the upper substrate holder is observed by at least one additional measurement system.

In a fourth embodiment of the method according to the invention, the process described is modified, whereby the order of loading the substrates is changed while the process results remain the same.

In the fifth embodiment of the method according to the present invention, the processing steps are parallelized to increase the speed, and the loading of the second substrate is already executed particularly during the pattern recognition step on the first substrate.

In the sixth embodiment of the method according to the invention and the corresponding apparatus, the position and / or orientation of both the upper substrate holder and the lower substrate holder and / or the upper substrate is provided by an additional measurement system. The position and / or orientation of both the and the lower substrate can be detected.

In a seventh embodiment of the method according to the invention and corresponding devices, an additional measuring system can be used to detect the position and / or orientation of the upper substrate holder and / or upper substrate.

All technically conceivable combinations and / or permutations, and multiplexing of functional and / or material parts of the device, and the inevitable changes associated thereto, are in at least one of multiple processing steps or methods. It is considered to be disclosed.

Where and / or in the description of the figures that follow, if a feature of the device is disclosed, this feature shall also be disclosed and valid as a feature of the method, and vice versa.

Another advantage, feature and detail of the invention can be obtained from the following description of preferred examples and by drawing.

It is the schematic sectional drawing of one Embodiment of the apparatus by this invention. FIG. 5 is a schematic enlarged cross-sectional view of the embodiment shown in FIG. 1 in the first processing step. It is a schematic enlarged sectional view in the 2nd processing step of the embodiment shown in FIG. It is a schematic enlarged sectional view in the 3rd processing step of the embodiment shown in FIG.

In the drawings, according to the embodiments of the present invention, the advantages and features of the present invention are shown by reference numerals that identify them, and the components or features of the same function or functions having the same function are the same reference numerals. It is indicated by.

FIG. 1 is a schematic and non-scaled functional diagram of the main constituent members of the first embodiment of the alignment device 1. The alignment device 1 is referred to as a substrate 16 (referred to as a first substrate and / or a lower substrate) and a substrate 17 (referred to as a second substrate and / or an upper substrate) not written in FIG. ) And / or the substrate laminates can be aligned with each other and at least partially bonded to each other and / or temporarily bonded (so-called prebonding). The possible movements / degrees of freedom of the functional components described below are symbolically drawn with arrows.

The first substrate 16 is loaded on the first substrate holder 10 and can be fixed to the first substrate holder 10 without leaving the degree of freedom of the substrate 16 with respect to the first substrate holder 10. The second substrate 17 is loaded on the second substrate holder 13 and can be fixed to the second substrate holder 13 without leaving the degree of freedom of the substrate 16 with respect to the second substrate holder 13.

In particular, the lower first substrate holder 10 is arranged in the first moving device 11 for holding the first substrate holder 10 and executing the supply motion and the position adjustment motion (alignment).

In particular, the upper second substrate holder 13 is arranged in the second moving device 14 for holding the second substrate holder 13 and executing the supply motion and the position adjustment motion (alignment). The moving devices 11 and 14 are particularly fixed to a common sturdy platform or frame 9 in order to reduce / minimize vibrations of all functional members.

In order to observe (detect) the first alignment mark 20 and the second alignment mark 21, the optical system 2 is composed of the following. That is,
− With respect to the first detection unit 3 which is an image detecting means for detecting the first alignment mark 20 of the first substrate 16.
-It is composed of a second detection unit 4 which is an image detecting means, which detects a second alignment mark of the second substrate 17.

When the first substrate 16 and the second substrate 17 are arranged for alignment, the optical system 2 is arranged between the first substrate 16 and the second substrate 17, preferably. It can be focused on a common focal plane 12. The movement of the optical system 2, particularly in the X, Y, and Z directions, is performed by using the positioning device 5 that positions the optical system 2. The positioning device 5 is fixed to a particularly sturdy base or frame.

In one embodiment (not shown), which is particularly preferred, the overall optics 2 (with positioning means 5, detection units 3 and 4, etc.) is used in the dual mirror symmetric embodiment.

A particularly optical additional at least one measurement system 6 including at least one third detection unit 7 improves alignment accuracy according to the present invention by detecting the third alignment mark 22. Used to make it. The movement of the additional measurement system is performed by the positioning device 8.

When the measuring device is an optical measuring system 6, the positioning device 8 can focus on the third alignment mark 22 by moving the third detection unit 7 in the Z direction. Positioning in the XY directions can be considered in the same manner, in which case the measurement system 6 is fixed to the table / frame during positioning, particularly preferably to the table / frame. Alternatively, the exact XY position of the measurement system 6 must be known.

In the illustrated embodiment of the alignment device 1 according to the invention, the additional measurement system 6 allows the lower substrate holder 10 to have a particularly high accuracy in the XY position and / or orientation (particularly in the rotational direction). Is detected by.

In another embodiment of the alignment device 1 (not shown) according to the invention, the additional measurement system detects the position and / or orientation of the upper substrate holder, especially the position and / or orientation, with particularly high accuracy.

In another embodiment of the alignment device 1 according to the invention (not shown), the additional measurement system detects the position and / or orientation of the upper and lower substrate holders with particularly high accuracy. ..

In another embodiment of the alignment device according to the invention (not shown), the position and / or orientation of at least one of the two substrates is detected with particularly high accuracy by at least one measurement system. For this purpose, the alignment mark on the contact surface and the mark on the surface opposite to the contact surface are detected.

FIG. 2a shows a schematic diagram of the processing steps according to the invention that associate the measurements of at least two detection units, in particular the different side surfaces of the first substrate 16 and / or the first substrate holder 10. A schematic diagram of a processing step according to the invention is shown that associates the measured values of two detection units that detect at least two XY positions of the alignment marks 20, 22 arranged in.

The first / lower substrate 16 is fixed to the first fixing surface 10a of the first substrate holder 10. The method of fixing is caused by the pressure difference between the ambient environment of the standard atmosphere and the negative pressure in the first substrate holder 10, which is also called mechanical clamp and / or electrostatic clamp or vacuum fixing. The pressing force formed by is used. This fixation is made in particular so that the first substrate 16 does not move relatively parasitically or undesirably with respect to the first substrate holder 10 during the overall method according to the invention. , Here, the first substrate holder 10 and the first substrate 16 each have a corresponding coefficient of thermal expansion, preferably a coefficient of thermal expansion that elapses correspondingly linearly, with a difference in coefficient of thermal expansion and / or When the difference in the linear course of the coefficient of thermal expansion is preferably 5% or less, preferably 3% or less, particularly preferably 1% or less, thermal expansion can be particularly prevented or reduced.

The above apparatus preferably has a temperature fluctuation during the alignment cycle of 0.5 Kelvin or less, preferably 0.1 Kelvin or less, particularly preferably 0.05 Kelvin or less, and optimally 0.01 Kelvin or less. Operates in a sustainable temperature-stabilized ambient environment, especially in a clean room.

The first substrate 16 and the first substrate holder 10 fixed so as not to move relative to each other can be understood as a pseudo monolithic body for moving the first substrate 16.

The substrate can be fixed by shape coupling and / or preferably by force coupling. Pseudo-monolithic bonding reduces at least the multiple effects that can cause misalignment and / or twisting and / or deformation between the substrate holder and the substrate, preferably by at least an order of magnitude, particularly preferably. Will be removed.

The plurality of effects described above may be thermal and / or mechanical, and / or flow-induced, and / or material (particles).

The substrate is fixed to the substrate holder by shape coupling or force coupling, which can suppress the difference in thermal expansion in particular. In addition, the substrate holder can reduce, remove, and / or correct deformation of the substrate itself. See European Patent No. 2656378 (EP2656378B1) for this.

During the detection of the first alignment mark 20, the first substrate holder 10 is in the optical path of the (upper) first detection unit 3. The first alignment mark 20 is arranged on the contact surface 16i to be bonded of the first substrate 16 in the field of view of the first detection unit 3 (upper side), particularly in the optical path. The first detection unit 3 forms a particularly digital image, abbreviated here as a cross-shaped alignment mark. The first alignment mark 20 can also be composed of a plurality of alignment marks. From the image of the alignment mark, in particular, the XY position of the first substrate 16 and / or the alignment direction (especially in the rotation direction around the Z direction), that is, the measured value that characterizes the alignment state is formed / calculated. To.

During the detection of the first alignment mark 20, the second / lower detection unit 4 preferably does not supply the measured value. This is because the second substrate 17 is particularly arranged / arranged outside the optical path of the first detection unit 3.

The first / lower substrate holder 10 and / or the first / lower substrate 16 has a third alignment mark 22, and the substrate holder is based on the third alignment mark 22. The XY position and / or the alignment direction (especially in the rotational direction around the Z direction) of the 10 and / or the first substrate (16), that is, the alignment state, is detected from a particularly different direction, preferably. It is detected in the radial direction from the direction opposite to the Z direction from the first detection.

Preferably, the relative movement of the first detection unit 3 with respect to the third detection unit 7 is measurable, or more preferably from the detection of the first positioning mark 20 and the third positioning mark 22. No relative movement is performed between the first detection unit 3 and the third detection unit 7 until the contact between the first substrate 16 and the second substrate 17.

The (additional) third detection unit 7 of the additional measurement system 6 is the first / lower substrate from the measurement of the third alignment mark 22 of the first / lower substrate holder 10. A measurement of the XY position and / or direction of the holder 10 is supplied. This measurement is formed, in particular, from a preferably digital image, symbolically drawn as a cross. The third alignment mark 22 can also be composed of a plurality of alignment marks.

Two measurements (XY position and / or alignment direction of the first substrate 16 and XY position and / of the third alignment mark 22 of the first substrate holder 10 or the first substrate 16). Or alignment directions) are associated with each other and / or correlated with each other, whereby the XY position and / or alignment direction of the first alignment mark 20 is always this XY position and / or alignment direction. It can be uniquely associated with the third alignment mark, especially by detecting the XY position and / or the alignment direction based on the alignment direction.

By this processing step, while the first substrate 16 and the second substrate 17 are aligned and / or brought into contact with each other, the first alignment mark 20 and / or the second alignment mark 21 is XY. Alignment is achieved without directly detecting the position and / or alignment direction. In addition, the spacing between the substrates can be minimized during alignment. This spacing can preferably be made to already correspond to the spacing of the substrates during the detection of the first alignment mark and the second alignment mark.

In other words, an unobstructed optical path is obtained, in particular between the substrate holder 10 and the additional measurement system 6, which allows the alignment of the substrate to be performed in the open control loop. Board alignment is performed. By this processing step, the XY position and / or the alignment direction of the first substrate holder 10 is changed, and thus the XY position and / or the alignment direction of the first substrate fixed to the first substrate holder 10. Can be accurately identified and reproducibly restored.

In particular, the restoration of the XY position and / or the alignment direction of the substrate holder 10, and the restoration of the XY position and / or the alignment direction of the substrate monolithically joined thereto are particularly unique core ones. There are two aspects. The processing steps for this have already been discussed elsewhere.

In particular, the repeatability of positioning (measured as a relative misalignment between two substrates), also known as play during inversion, is 1 micrometer or less, preferably 100 nm or less, particularly preferably 30 nm or less. Particularly, it reaches 10 nm or less, 5 nm or less in the optimum case, and 1 nm or less in the ideal case. This play at the time of reversal may be repeated arrival at a predetermined position using the moving devices 11, 14 and / or 5, 8. This play at the time of inversion occurs as a result of the movement of the moving device, which changes only the detection position, so that the measured quantity becomes a relative misalignment. The positioning accuracy of the moving device, which does not affect the substrate, can be regarded as unrelated play during inversion.

According to the present invention, it is preferable to operate the first detection unit 3 and the third detection unit 7 in time synchronization, particularly for 10 minutes, in order to further improve the positioning accuracy. Detection of measured values of 1 second or less, preferably 1 millisecond or less, particularly preferably 10 microseconds or less, particularly extremely preferably 1 microsecond or less, optimally 1 ns or less, ideally 0.0 ns or less. It is to operate with a time difference. This is especially advantageous. This is because obstructive effects such as mechanical vibration can be removed. Mechanical vibrations propagate through the material, especially with solid-state transmission sounds at thousands of m / s. If the closed-loop control and detection means operate faster than the solid-state transmission sound propagation velocity, the obstacles are reduced or eliminated.

Due to the failure, the orientation of the first substrate 16 in the first substrate holder 10 is changed, whereby the first detection unit 3 has already recorded the measured values, but is an additional one with the detection unit 7. This failure can be part of a loss of alignment accuracy if the measurement system 6 has not yet recorded the measurements. This is because in the time between the recording of the measurements of the detection means 3 and 7, high-speed position changes, especially due to vibration, can occur on the order of nanometers or micrometers. If the recording of measurements is delayed in time (on the order of seconds or minutes), other obstructive effects such as temperature-induced shape or length changes will also provide alignment accuracy. Can be reduced.

Some if the first detection unit 3 and the third detection unit 7 are synchronized with each other (especially due to simultaneous triggering of detections and adjustment of detection time and / or the same integration time for the camera system). Obstacle effects can be reduced and eliminated in optimal cases. This is because the detection is performed at the time when the faulty effect affects the detection accuracy with the least possible effect.

In one possible embodiment of the device, it is possible to perform detection, especially in synchronization with the poles of vibration, especially when periodic impaired effects are known. For this purpose, preferably, a vibration sensor (accelerometer, interferometer, vibrometer) at a location of the device related to accuracy records an obstacle effect in advance, and in order to remove it, it is processed especially in a calculation unit or a computer. be able to. In another embodiment, a plurality of vibration sensors can be fixedly incorporated in a characteristic portion of the device.

In another possible embodiment, the device is, in particular, an active and / or passive vibration attenuator, an active and / or passive vibration extinguisher, and / or an active and / or passive vibration. It can be implemented and used in a combination of insulators, or these can be cascaded and used. In addition, it is possible to superimpose the vibration on the forced vibration as an obstacle effect, thereby performing a so-called lock-in method for detecting the alignment mark. Mode analysis and / or FEM can be used to characterize the device and to check the vibrational state. This and the design of such devices are known to those of skill in the art.

Before, during, or after the detection of the first alignment mark 20 and the third alignment mark 22, the first detection unit 3 and the third detection unit 7 are clamped, at least absolutely and absolutely. / Or reduce the relative degrees of freedom in the X and Y directions to zero. Relative is the movement of the first detection unit 3 with respect to the third detection unit 7.

FIG. 2b is a schematic diagram of a processing step according to the present invention for detecting a measured value on the second / upper substrate 17. The optical system 2 is in particular already in a clamped state, and an image and / or XY position of at least one alignment mark on the first / lower substrate 16 is stored (not shown). ). In the clamped state, at least the absolute and / or relative degrees of freedom of the second detection unit with respect to the first detection unit in the X and Y directions are reduced to zero.

In the clamped state, the XY positions and / or alignment directions of the first, second and third alignment marks can be associated with the same XY coordinate system. Alternatively or additionally, the first, second and third detection units are calibrated in the same XY coordinate system.

The second / upper substrate 17 fixed to the second / upper substrate holder 13 is moved to the detection position by the second moving device 14 that moves the second substrate holder 13, and the second / lower substrate 17 is moved. The detection unit 4 on the side detects / captures the XY position and / or the alignment direction of the second alignment mark 21 on the second substrate 17.

The goal is to align the second substrate 17 as perfectly as possible with respect to the XY position and / or orientation of the first / lower substrate 16. The lower substrate 16 can be an obstacle in the optical path for observing the second alignment mark 21 of the second / upper substrate 17 by the second detection unit 4, so that the lower substrate 16 is particularly in the X direction and / or Y. By moving in the direction, the first / lower substrate 16 is moved out from this optical path, preferably without moving in the Z direction.

The correction of the XY positions and relative directions of the two substrates is performed by comparing the XY positions and / or the alignment directions of the first alignment mark and the second alignment mark with the third alignment. It is done in correlation with the mark.

After the alignment of the second / upper substrate is achieved with particularly minimal misalignment, preferably with the misalignment removed, the upper substrate holder is clamped, i.e., at least in this processing step. It takes away the degree of freedom in the X and Y directions.

FIG. 2c illustrates a processing step according to the invention, particularly for aligning the first substrate 16 with respect to the clamped second substrate 17.

The optical path of the optical system 2 is blocked between the first detection unit 3 and the second detection unit 4 by the first substrate holder 10 and the second substrate holder 13 during alignment. Therefore, the detection units 3 and 4 cannot be used during the alignment.

In a particularly preferred embodiment, the additional measurement system 6 with a third detection unit 7, which is a camera system with a microscope, preferably in real time, especially continuously, with XY position closed loop control and / Alternatively, it forms image data that can be used as raw data for directional closed loop control.

The (theoretical or average) spacing (particularly not considering possible preload or deflection) of the contact surfaces 16i, 17i to be bonded is particularly less than 1 mm, preferably less than 500 micrometers, particularly preferably 100 micrometers. Below, the optimum case is 50 micrometers or less, and the ideal case is 10 micrometers or less. In particular, this interval can be set by the mobile device 11 and / or the mobile device 14.

In particular, the target values determined / determined according to FIG. 2a are used to align the substrates 16 and 17. In particular, the target value includes the image data of the third alignment mark 22 of the first substrate holder 10 and / or the obtained XY position data and / or the obtained XY position data with respect to the moving device 11 of the first substrate holder 10. It also includes alignment direction data and / or closed-loop control parameters such as trajectories for optimally reaching the XY position, and / or machine-readable values specifically for the drive.

In another embodiment, the remaining error that was not removed when positioning the upper and / or lower board can be considered as a correction value for the positioning of another (lower or upper) board. is there.

The first substrate holder 10 minimizes the alignment error calculated from the target value of the additional measurement system and the actual position and / or orientation of the substrate holder and is ideally removed until it is removed or Until the determination of interruption is reached, the first moving device 11 moves the position in a closed-loop controlled manner and particularly in a closed-loop controlled manner. In other words, the lower substrate holder 10 is returned to the already known measured XY alignment position in a controlled, closed-loop controlled manner.

In another embodiment, the remaining errors that were not removed when positioning the upper and / or lower board are similarly considered as corrections for the positioning of another (lower or upper) board. It is possible.

Other correction factors can be obtained, in particular, from the vibrational state of the device or equipment part as previously described, where these correction factors are used to position the substrate and the uncertainty of the positioning residue. And improve the alignment accuracy. To verify the final position, again, all known failure factors and effects can be considered and corrected accordingly.

Finally, in this processing step according to the present invention, the movement of the substrate holders 10 and 13 in the XY directions is prevented by clamping all the driving units.

After aligning the substrates 16 and 17 according to one of the plurality of methods according to the present invention, in order to bond these substrates to each other by prebonding, at least one of the plurality of substrates is attached to the substrate deforming device 15. Can be deformed in the direction of another substrate.

1 Alignment device 2 Optical system 3 1st / upper detection unit 4 2nd / lower detection unit 5 Positioning device 6 Additional measurement system 7 3rd / additional detection unit 8 Additional measurement System Positioning Device 9 Frame 10 1st Board Holder 10a 1st Fixed Surface 11 1st Moving Device 12 Common Theoretical Focus Plans of Optical Systems 13 2nd / Upper Board Holder 13a 2nd Fixed Surface 14 Second moving device 15 Board deforming device 16 Lower board 16i First contact surface 16o First mounting surface 17 Upper board 17i Second contact surface 17o Second mounting surface 20 First position Alignment mark 21 Second alignment mark 22 Third alignment mark

Claims (13)

A method of aligning and contacting the first contact surface (16i) of the first substrate (16) and the second contact surface (17i) of the second substrate (17), as follows. The steps are specifically in the following order, i.e.
-The first mounting surface (16o) of the first substrate (16) is fixed to the first substrate holder (10), and the second mounting surface (17o) of the second substrate (17) is fixed. Is fixed to the second substrate holder (13) which can be arranged so as to face the first substrate holder (10).
-Especially with reference to the focal plane (12) of the first detection unit (3), the first of the first alignment marks (20) arranged in the peripheral region of the first substrate (16). And / or the step of detecting the XY position and / or the first alignment direction of
-Especially with reference to the focal plane (12) of the second detection unit (4), the second of the second alignment mark (21) arranged in the peripheral region of the second substrate (17). And / or the step of detecting the XY position and / or the second alignment direction of
-A step of aligning the first substrate (16) with respect to the second substrate (17).
-In a method having a step of bringing the first substrate (16) aligned with respect to the second substrate (17) into contact with the second substrate (17).
At the same time as the detection of the first alignment mark (20 ), the third X of the third alignment mark (22) of the first substrate holder (10) and / or the first substrate (16) . The −Y position and / or the third alignment direction is additionally detected by the third detection unit (7), and the alignment is open-loop controlled by using the third detection unit (7). On the surface on which the first alignment mark (20) and the third alignment mark (22) are different from each other, particularly, the first substrate (16) or the first substrate holder (10). ), Which are located on opposite sides of each other in the Z direction .
The first XY position and / or the first alignment direction of the first alignment mark (20) is the third XY position of the third alignment mark (22). And / or uniquely associated with the third alignment direction,
A method characterized by that. The detection of the first alignment mark (20) and the third alignment mark (22), the associated processing steps, the the previous SL first detection unit (3) third detection unit ( Performed by synchronizing with 7),
The method according to claim 1. During the alignment, the second substrate holder (13) is fixed at least in the XY directions.
The method according to claim 1 or 2. The first detection unit (3) and the second detection unit (4) are attached to a common XY positioning device, and / or the optical axis of the first detection unit (3) and The optical axes of the second detection unit (4) are aligned or associated with each other and preferably have a common optical axis.
The method according to any one of claims 1 to 3. An optical system (2) comprising the third detection unit (7) with respect to at least the first detection unit (3), particularly the first detection unit (3) and the second detection unit (4). ), The position is fixed in the X direction and the Y direction until at least the alignment is performed during the detection, and preferably there is no degree of freedom.
The method according to any one of claims 1 to 4. The open-loop control of the alignment is performed only by the detection of the third XY position and / or the third alignment direction.
The method according to any one of claims 1 to 5. A particularly constant distance A is provided between the first contact surface and the second contact surface in the Z direction until the first substrate and the second substrate are detected and aligned. Provided and arranged between the first substrate holder and the second substrate holder.
The method according to any one of claims 1 to 6. The interval A is 500 micrometers or less, particularly preferably 100 micrometers or less, in the optimum case 50 micrometers or less, and in the ideal case 10 micrometers or less.
The method according to claim 7. A device for aligning and contacting a first contact surface (16i) of a first substrate (16) and a second contact surface (17i) of a second substrate (17).
− With the first substrate holder (10) for fixing the first mounting surface (16o) of the first substrate (16).
-A second substrate holder (13) that can be arranged to face the first substrate holder (10) that fixes the second mounting surface (17o) of the second substrate (17).
-With the first detection unit (3) for detecting the first XY position and / or the first alignment direction of the first alignment mark (20).
-The second detection unit (4) that detects the second XY position and / or the second alignment direction of the second alignment mark (21), and
-Alignment means for aligning the first substrate (16) with respect to the second substrate (17), and
-A contact means (15) for bringing the first substrate (16) aligned with the second substrate (17) into contact with the second substrate (17).
In the device with
The apparatus detects the first alignment mark (20), and at the same time, the first substrate holder (10) and / or the third alignment mark (22) of the first substrate (16). It has a third detection unit (7) that detects the XY position of 3 and / or the third alignment direction, and the alignment is opened by using the third detection unit (7). a possible loop control, and the first alignment mark (20), and the third alignment mark (22) on the surface of different sides, in particular, the first substrate (16) or the second The substrate holders (10) of No. 1 are arranged on the surfaces opposite to each other when viewed in the Z direction .
The first XY position and / or the first alignment direction of the first alignment mark (20) is the third XY position of the third alignment mark (22). And / or uniquely associated with the third alignment direction,
A device characterized by that. The first detection unit (3) and the third detection unit (7) are synchronous or synchronized.
The device according to claim 9. During the alignment, the second substrate holder (13) is configured to be fixed at least in the XY directions.
The device according to claim 9. The first detection unit (3) and the second detection unit (4) are attached to a common XY positioning device, and / or the optical axis of the first detection unit (3) and The optical axes of the second detection unit (4) are aligned or associated with each other and preferably have a common optical axis.
The device according to claim 9. The third detection unit (7) is an optical system (2) composed of at least the first detection unit (3), particularly the first detection unit (3) and the second detection unit (4). ), It is positioned fixedly in the X and Y directions during the detection, at least until it is aligned, and preferably has no degree of freedom.
The device according to claim 9.

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